a) Field of the Invention
The present invention relates to the methods for locating an impact on a surface and to the devices for implementing those methods.
b) State of the Art
More particularly, the invention concerns a method for locating an impact on a surface forming part of an object forming an acoustic interface, provided with at least one acoustic sensor (the object forming an acoustic interface may be made of a single piece or of several elements, assembled or at least in mutual contact), a method in which at least one signal is sensed from acoustic waves generated in the object forming an acoustic interface by said impact and the impact is located by processing of said sensed signal.
The document FR-A-2 811 107 describes an example of such a method that applies in particular to a pane. In this known method, the position of the impact on the surface of the object is computed by measuring the differences in time for the acoustic waves to fly to different sensors.
This known method however requires:                that the pane used have a perfect homogeneity and a perfect surface state,        that the fields of the pane be specially treated, particularly to avoid reflections of the acoustic waves,        that the speed of the acoustic waves in the pane be known in advance, which assumes a precise knowledge of its composition,        that at least four sensors be used.        
As a result, this known method is particularly costly to implement and cannot be applied to any preexisting objects, particularly heterogeneous objects consisting of assemblies of pieces, irregular shaped objects, etc.
The aim of the present invention is in particular to alleviate these disadvantages.